Best MC Load Resistor Type, current gain stage...

tubenut · 18th August 2006, 10:13 PM

Hi all

I am inviting opinions.

My phono pre (Electrocompaniet) uses current amplification.
I messed a little with the input load resistor value (10R) onlly to go back to the original value of 10R. I used a fresh commercial grade metal film resistor. The sound just seemed wrong.
Replaced with the original "used" resistors and a all was well.

So what is your favourite load resistor type:
Vishay Bulk MF?
Tantalum?
Precision Carbon?
Any number of Metal Films from Holco, PRP etc?

I guess experience with passive I/V CD stage resistor types would count here as well.

Ta

SY · 18th August 2006, 11:42 PM

Bulk metal foil in that position.

anatech · 19th August 2006, 02:06 AM

Hi SY,
Is there that much of a difference? Naked foil or bare (I'm guessing sealed / coated)?

There can be differences in metal film types that are measurable.

-Chris

SY · 19th August 2006, 02:40 AM

The ones I have are sealed in little square epoxy packages. I'm not sure of the brand- got 'em as a gift.

anatech · 19th August 2006, 02:43 AM

Sy,
You're one lucky fella. Good going!

One fella was recommending the naked bulk metal foil over the encapsulated ones because "he could hear a difference". Physiology is a wonderful thing. They cost more he says, that must be it!

That's like having a naked capacitor! Okay, low voltage.

-Chris

AndrewT · 19th August 2006, 09:20 AM

Hi,
if a wire (non inductive wound) resistor were made, what material should sound best?

Copper, constantan, nichrome? Others?

sreten · 19th August 2006, 10:57 AM

Hi,

For a virtual earth current amplifier the best load resistor is none at all !

/sreten.

anatech · 19th August 2006, 01:57 PM

Hi sreten,
Can't argue that, except you still need a sensing element. That would be doped silicon in most cases (ultimately).

-Chris

sreten · 19th August 2006, 02:31 PM

Hi,

To be accurate the cartridge internal resistance becomes the "load"
resistor and the virtual earth current stages voltage gain becomes
directly dependant on the cartridges impedance, self adjusting.

Adding a 10R series "load" resitor simply makes the gain changes
less severe as the cartridge source resistance changes, whether
this is a good idea or not depends on the internal gain setting.

/sreten.

tubenut · 19th August 2006, 03:24 PM

I think the 10R sit from signal in to ground, that is parallel not series?

18th August 2006, 10:13 PM	#1
tubenut diyAudio Member Join Date: Nov 2002 Location: South Africa, Jhb	Best MC Load Resistor Type, current gain stage... Hi all I am inviting opinions. My phono pre (Electrocompaniet) uses current amplification. I messed a little with the input load resistor value (10R) onlly to go back to the original value of 10R. I used a fresh commercial grade metal film resistor. The sound just seemed wrong. Replaced with the original "used" resistors and a all was well. So what is your favourite load resistor type: Vishay Bulk MF? Tantalum? Precision Carbon? Any number of Metal Films from Holco, PRP etc? I guess experience with passive I/V CD stage resistor types would count here as well. Ta __________________ Guillaume Croak Audio Exploration

18th August 2006, 11:42 PM	#2
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	Bulk metal foil in that position. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

19th August 2006, 02:40 AM	#4
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	The ones I have are sealed in little square epoxy packages. I'm not sure of the brand- got 'em as a gift. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

19th August 2006, 09:20 AM	#6
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, if a wire (non inductive wound) resistor were made, what material should sound best? Copper, constantan, nichrome? Others? __________________ regards Andrew T.

19th August 2006, 03:24 PM	#10
tubenut diyAudio Member Join Date: Nov 2002 Location: South Africa, Jhb	I think the 10R sit from signal in to ground, that is parallel not series? __________________ Guillaume Croak Audio Exploration


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19th August 2006, 02:06 AM	#3
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi SY, Is there that much of a difference? Naked foil or bare (I'm guessing sealed / coated)? There can be differences in metal film types that are measurable. -Chris

19th August 2006, 02:43 AM	#5
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Sy, You're one lucky fella. Good going! One fella was recommending the naked bulk metal foil over the encapsulated ones because "he could hear a difference". Physiology is a wonderful thing. They cost more he says, that must be it! That's like having a naked capacitor! Okay, low voltage. -Chris

19th August 2006, 10:57 AM	#7
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Hi, For a virtual earth current amplifier the best load resistor is none at all ! /sreten.

19th August 2006, 01:57 PM	#8
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi sreten, Can't argue that, except you still need a sensing element. That would be doped silicon in most cases (ultimately). -Chris

19th August 2006, 02:31 PM	#9
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Hi, To be accurate the cartridge internal resistance becomes the "load" resistor and the virtual earth current stages voltage gain becomes directly dependant on the cartridges impedance, self adjusting. Adding a 10R series "load" resitor simply makes the gain changes less severe as the cartridge source resistance changes, whether this is a good idea or not depends on the internal gain setting. /sreten.

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